1. Field of the Invention
The present invention relates to a disk drive, and more particularly, to an optical pickup system for reciprocating an optical pickup head in a radial direction of a disk.
2. Description of the Related Art
Generally, a disk drive is an apparatus to read data from and/or write data on a disk-type optical medium (hereinafter referred to as an optical disk), and includes an optical pickup system for reciprocating an optical pickup head in a radial direction of the optical disk.
FIG. 1 is a top view depicting one example of a conventional main base 10, and FIG. 2 is a cross-sectional view depicting the main base in FIG. 1, to which a step motor 17 and a lead screw 16 are mounted. Referring to FIG. 1, the main base 10 is provided with a turntable 12 rotatably installed on the main base 10 in a coaxial relation with a spindle motor 11 and having an optical disk D seated thereon. The main base 10 further includes an optical pickup head 13 for writing the data on the optical disk D or reading the data from the optical disk D, and an optical pickup system for reciprocating the optical pickup head 13 in a radial direction of the optical disk.
The optical pickup system includes a pair of guide rails 14 and 15 for guiding the optical pickup head 13 to reciprocate in the radial direction of the optical disk D. The lead screw 16 installed in parallel to the guide rails 14 and 15 and has threaded grooves 16a formed on an outer periphery thereof. The stepping motor 17 is coupled to the lead screw 16 for rotating the lead screw 16. A slider 18 has one end secured to the optical pickup head 13 and the other end meshed with the threaded grooves 16a, so that rotary motion of the lead screw 16 is converted into linear motion to reciprocate the optical pickup head 13 in the radial direction of the optical disk D.
Referring to FIG. 2, the lead screw 16 is rotatably supported by a bracket 21 fixed to a plurality of supports 19 by means of screws 20. The supports 19 one fixed to the main base 10. The stepping motor 17 is coupled to the lead screw 16 to rotate the lead screw 16. As shown in FIG. 2, the screws 20 fit precisely in the bracket 21 and do not move relative to the bracket 21.
With the above construction, when the lead screw 16 is turned by the stepping motor 17, the optical pickup head 13 is reciprocated by the slider 18 in the radial direction of the optical disk D to write the data on the disk D or read the data from the disk D. In order to transfer a torque of the lead screw 16 to the slider 18, the slider 18 is meshed with the lead screw 16. Therefore, the lead screw 16 and the slider 18 should have a precise tolerance to smoothly transfer the power.
When assembling the optical pickup system, the slider 18 may become meshed with the lead screw 16 away from a tolerance range, or the lead screw 16 may be in or out of a parallel relation with the guide shaft 14 due to an external shock. In this case, the slider 18 is not properly meshed with the lead screw 16, so that the power is not smoothly transferred. A deviation in the assembly of the lead screw 16 and the slider 18 serves as a load to the lead screw 16 and thus to the stepping motor 17, which excessively consumes the electric current.